A sleeve valve as employed in an internal combustion engine generally includes one or more machined sleeves that fit between a piston and a cylinder wall. Conventional sleeve valves generally rotate and slide to periodically align one or more ports in the sleeve valve body with inlet and/or exhaust ports formed in the cylinder walls in accordance with the cycle requirements of the engine.
Sleeve valves have been described for use in opposed piston engines in which two pistons share a single cylinder such that no cylinder head is needed. For example, co-owned U.S. Pat. No. 7,559,298, which is incorporated herein by reference, describes such an engine configuration.